Sibley County is a county located in the U.S. state of Minnesota. As of 2000, the population was 15,356. Its county seat is Gaylord.
According to the U.S. Census Bureau, the county has a total area of 600 square miles (1,555 kmē), of which 589 square miles (1,525 kmē) is land and 12 square miles (30 kmē) (1.96%) is water. Most of the Rush River's watershed is located in Sibley County.